36709-10-1Relevant academic research and scientific papers
Is the reaction between CH3C(O)O2 and NO3 important in the night-time troposphere?
Canosa-Mas, Carlos E.,King, Martin D.,Lopez, Reyes,Percival, Carl J.,Wayne, Richard P.,Shallcross, Dudley E.,Pyle, John A.,Daele, Veronique
, p. 2211 - 2222 (1996)
A discharge-flow system equipped with a laser-induced fluorescence (LIF) cell to detect NO2 and a multi-pass absorption cell to detect NO3 has been used to study the reaction CH3C(O)O2 + NO3 → CH3C(O)O + NO2 + O2 (1) at T = 403-443 K and P = 2-2.4 Torr. The rate constant was found to be independent of temperature with a value of k1 = (4 ± 1) × 10-12 cm3 molecule-1 s-1. The likely mechanism for the reaction is discussed. The atmospheric implications of reaction (1) are investigated using a range of models and several case studies are presented, comparing model results with actual field measurements. It is concluded that reaction (1) participates in a cycle which can generate OH at night. This reaction cycle (see text) can operate throughout the continental boundary layer, but may even occur in remote regions.
The CH3C(O)O2 Radical. Its UV Spectrum, Self-Reaction Kinetics, and Reaction with CH3O2
Maricq, M. Matti,Szente, Joseph J.
, p. 4507 - 4513 (1996)
The reactions of CH3C(O)O2 with itself and with CH3O2 are investigated using flash photolysis combined with time-resolved UV spectroscopy and transient infrared absorption.The UV spectrum of CH3C(O)O2 exhibits two bands; the stronger short wavelength component has a maximum cross section of 6.5E-18 cm2 at 206 nm and the weaker one a cross section of 2.9E-18 cm2 at 250 nm.These bands are used to monitor the disappearance of CH3C(O)O2 and the secondary formation of CH3O2, yielding a self-reaction rate constant of (3.0 +1.7/-1.1)E-12 e(504 +/- 114)/T cm3 s-1 and a cross reaction rate constant of (8.5 +2.6/-2.0)E-13 e(726 +/- 75)/T cm3 s-1.Transient IR monitoring of the formation of CH2O reveals CH3C(O)O2 + CH3O2 -> CH2O + CH3COOH + O2 to be the dominant channel for the cross reaction over the entire 209-358 K temperature range.This contrasts with previous studies that indicate a steep temperature dependence for the branching ratio, with a channel leading to CH3C(O)O + CH3O + O2 dominant at high temperatures.
Reactions of Peroxyacetyl Radicals with Reduced Sulfur Compounds
Mineshos, Gerassimos,Glavas, Sotirios,Schurath, Ulrich
, p. 501 - 508 (1992)
The reaction of peroxyacetyl radicals with reduced sulfur compounds was studied at 55 deg C in N2 at 1000 mbar total pressure.The radicals were generated in equilibrium with peroxyacetyl nitrate and NO2 in large excess.The pseudo first order decay of PAN was measured in the absence and presence of several 100 ppm CH3SH, C2H5SH, n-C4H9SH, (CH3)2S and (CH3s)2.Computer simulations yielded the following rate constants of peroxyacetyl radicals with the above mentioned sulfur compounds: 3.7, 2.8, 13.0, 0.9, and 1.8*10-16 cm3/s, respectively.An electron capturing compound of the thiols with NO2 was observed.Keywords.Reactions; PAN; Sulfur compounds.
Absorption Spectrum and Kinetics of the Acetylperoxy Radical
Roehl, Coleen M.,Bauer, Dieter,Moortgat, Geert K.
, p. 4038 - 4047 (1996)
The ultraviolet absorption spectrum of acetylperoxy radical was remeasured in the 195-280 nm range.Acetylperoxy radicals were generated by laser flash photolysis of Cl2/CH3CHO/O2 mixtures.The absorption cross sections were calibrated against the ethylperoxy radical, generated in the flash photolysis of Cl2/C2H6/O2 mixtures.The acetylperoxy spectrum is bimodal, with a strong maximum at 207 nm, ? = 6.67E-18 cm2 molecule-1, and a weaker maximum near 240 nm, ? = 3.21E-18 cm2 molecule-1.Newly obtained cross section were used along with absorption-time profiles, obtained over a range of radical concentrations, to determine a rate constant for the acetylperoxy self reaction at 298 K, 2CH3C(O)O2 -> 2CH3C(O)O + O2, of k1 = (1.36 +/- 0.19)E-11 cm3 moleclule-1 s-1, and to determine the rate coefficients for the acetyl- and methylperoxy cross reactions at 298 K, CH3C(O)O2 + CH3O2 -> CH3C(O)O + CH3O + O2 and CH3C(O)O2 + CH3O2 -> CH3C(O)OH + HCHO + O2, of k4a = (8.8 +/- 1.5)E-12 cm3 molecule-1 s-1 and k4b = (1.0 +/- 0.5)E-12 cm3 molecule-1 s-1, respectively.New cross sections are reported for CH3O2 and HO2 and the absorption spectrum of CH3COCl is presented.
Absorption Spectrum and Kinetics of Reactions of the Acetylperoxy Radical
Moortgat, G.,Veyret, B.,Lesclaux, R.
, p. 2362 - 2368 (1989)
The ultraviolet absorption spectrum of the acetylperoxy radical was measured in the range 190-280 nm.The radical was generated by flash photolysis of Cl2/CH3CHO/O2 mixtures.The absorption spectrum was calibrated against the HO2 radical generated in the Cl
Absolute rate constants for F + CH3CHO and CH3CO + O2, relative rate study of CH3CO + NO, and the product distribution of the F + CH3CHO reaction
Sehested, Jens,Christensen, Lene K.,Nielsen, Ole J.,Wallington, Timothy J.
, p. 913 - 921 (2007/10/03)
Using a pulse-radiolysis transient UV-VIS absorption system, rate constants for the reactions of F atoms with CH3CHO (1) and CH3CO radicals with O2 (2) and NO (3) at 295 K and 1000 mbar total pressure of SF6 was determined to be k1 = (1.4 ± 0.2) × 10-10, k2 = (4.4 ± 0.7) × 10-12, and k3 = (2.4 ± 0.7) × 10-11 cm3 molecule-1 s-1. By monitoring the formation of CH3C(O)O2 radicals (A > 250nm) and NO2 (A = 400.5nm) following radiolysis of SF6/CH3CHO/O2 and SF6/CH3CHO/O2/NO mixtures, respectively, it was deduced that reaction of F atoms with CH3CHO gives (65 ± 9)% CH3CO and (35 ± 9)% HC(O)CH2 radicals. Finally, the data obtained here suggest that decomposition of HC(O)CH2O radicals via C - C bond scission occurs at a rate of 5 S-1.
Absolute and relative rate constants for the reactions CH3C(O)O2 + NO and CH3C(O)O2 + NO2 and thermal stability of CH3C(O)O2NO2
Sehested, Jens,Christensen, Lene Krogh,M?gelberg, Trine,Nielsen, Ole J.,Wallington, Timothy J.,Guschin, Andrei,Orlando, John J.,Tyndall, Geoffrey S.
, p. 1779 - 1789 (2007/10/03)
A pulse-radiolysis system was used to measure absolute rate constants for the reactions of CH3C(O)O2 radicals with NO and NO2 at 295 K and 1000 mbar total pressure of SF6. When the rate of formation and decay of NO2 using its absorption at 400.5 and 452 nm were monitored, the rate constants k(CH3C(O)O2 + NO) = (2.0 ± 0.3) × 10-11 and k(CH3C(O)O2 + NO2) = (1.0 ± 0.2) × 10-11 cm3 molecule-1 s-1 were determined. Long path-length Fourier transform infrared spectrometers were used to study the rate-constant ratio k(CH3C-(O)O2 + NO)/k(CH3C(O)O2 + NO2) in 6-700 Torr total pressure of N2 diluent at 243-295 K. At 295 K in 700 Torr of N2 diluent k(CH3C(O)O2 + NO)/k(CH3C(O)O2 + NO2) = 2.07 ± 0.21. The results are discussed in the context of the atmospheric chemistry of acetylperoxy radicals.
Unimolecular Decomposition of Peroxynitrates
Zabel, F.
, p. 119 - 142 (2007/10/02)
Thermal decomposition rate constants of peroxynitric acid (HO2NO2) and chloromethyl peroxynitrate (CH2ClO2NO2) were measured as a function of temperature and total pressure in a photochemical reaction chamber of 420 l volume.Peroxynitrate concentrations were monitored by long-path IR absorption using a Fourier transform spectrometer.Analysis of these results in terms of unimolecular reaction rate theories yields kinetic parameters which allow to calculate decomposition rate constants of HO2NO2 and CH2ClO2NO2 for all pressures and temperatures which are of interest for atmospheric applications.These results, together with kinetic data on the thermal decomposition of other peroxynitrates previously obtained in our laboratory, allow to rationalize the change of the bond energies in peroxynitrates (RO2-NO2) with the nature of the group R.Combination of the decomposition data with experimental results on the reverse reactions from the literature are used to determine thermochemical data of peroxynitrates. - Keywords: Peroxynitric acid / Peroxynitrates / Thermal decomposition
Determination of the Rate Constant Ratio for the Reactions of the Acetylperoxy Radical with NO and NO2
Kirchner, F.,Zabel, F.,Becker, K. H.
, p. 1379 - 1382 (2007/10/02)
The thermal decomposition of acetyl peroxynitrate was studied in a 420 l DURAN glass reaction chamber in the presence of different initial / ratios.From an analysis of the rate data, the following rate constant ratios k2/k1 for the reactions of CH3C(O)O2 radicals with NO (k1) and NO2(k2) were derived at different temperatures and total pressures: 0.45 +/- 0.05 (304 K, 1000 mbar), 0.41 +/- 0.05 (321 K, 1000 mbar), 0.42 +/- 0.02 (313 K. 1000 mbar), 0.39 +/- 0.02 (313 K, 300 mbar), 0.28 +/- 0.04 (313 K, 100 mbar), 0.25 +/- 0.04 (313 K, 30 mbar).Using recent data on k2, a pressure independent rate constant k1 = (2.1 +/- 0.5)*10-11 cm3 molecule-1 s-1 was deduced from these ratios at 313 K.
Reaction of Acetaldehyde and Acetyl Radical with Atomic and Molecular Oxygen
Miyoshi, Akira,Matsui, Hiroyuki,Washida, Nobuaki
, p. 5813 - 5818 (2007/10/02)
The reaction of acetaldehyde with atomic oxygen, O(3P), was studied by the discharge-flow-photoinization mass spectrometry method at room temperature (295 +/- 4 K) for the conditions of excess atomic oxygen.The rate constant for reaction 1, CH3CHO + O -> CH3CO + OH, was (3.9 +/- 0.3) x 10-13 cm3 molecule-1 s-1.Branching fractions for the subsequent reactions 2a, CH3CO + O -> CH2CO + OH, and 2b, CH3CO + O -> CH3CO + O -> CH3 + CO2, were determined to be 22 +/- 5 percent and 76 +/- 24 percent, respectively.The experiments in the presence of molecular oxygen show that the ratio of rate constants for reaction 3, CH3CO + O2 + M -> CH3CO3 + M, to reaction 2 is (6.3 +/- 0.5) x 10-3 .From the rate constant for reaction 3 obtained by McDade et al., the rate constant for reaction 2 was calculated: k2 = (3.2 +/- 0.7) x 10-10 cm3 molecule-1 s-1.When the concentration of molecular oxygen increased, the yields of both CH3 and CH2CO decreased.From this decrease, the branching fractions for reactions 4a, CH3CO3 + O -> CH2CO + OH + 02, and 4b, CH3CO3 + O -> CH3 + CO2 + O2, were determined: A discussion of the other products from CH3CO3 + O is presented.
